PV diagram along the major axis. Gray contours and the color scale show the data, and blue contours show the best-fit model. Contours are at 1.5, 3, 6, 12, 24 × σ with σ = 0.24 mJy beam⁻¹ (3.2 × 10¹⁸ cm⁻² in a channel). The dashed gray line indicates the spatial fitted center, and the dashed colored line indicates the fitted systemic velocity of the best-fit model. The blue circles indicate the V_obs = V_rot × sin(i) of the best-fit model, and the white circles the same for the rising model (see text). To be concurrent with the right ascension, offsets are decreasing from left to right.